Showing papers on "Rectifier published in 1970"

A feedback-controlled ferroresonant voltage regulator

Abstract: A new regulated rectifier which combines a ferroresonant regulator with a simple control circuit is described herein. The voltage regulating function normally provided in a ferroresonant regulator by the saturating core is provided by the control circuit in this new regulated rectifier. The control circuit provides regulation by varying the amplitude of the alternating voltage feeding the rectifier and filter. By incorporating feedback into the control circuit, regulation of better than ±1/2 percent for line, load, frequency, and temperature changes can easily be attained. The new feedback-controlled circuit retains many desirable properties of conventional ferroresonant regulators such as half-cycle transient response, good input power factor, ideal output waveform for rectification and filtering, high efficiency, short circuit protection, and suppression of input voltage spikes. Additional features are level set, improved efficiency, lower stray magnetic fields than observed with conventional ferroresonant regulators, and, primarily, precision regulation. Data on an 800-watt regulated rectifier employing the new circuit are also presented.

Circuit for keeping the frequency of an inverter synchronized with the frequency of another source

Abstract: In an uninterruptible power supply comprising a normal source of alternating voltage, a rectifier/battery charger, a battery, and a static inverter, the inverter is kept in synchronism with the normal source by controlling its frequency in accordance with an error signal which is representative in magnitude and polarity of any deviation in phase between the output voltage of the inverter and the voltage of the normal source.

Automatic temperature responsive battery charging circuit

Abstract: A charger for charging a battery at a first predetermined rate and automatically terminating said charge rate when the battery temperature rises, in response to the charging current, to a point indicating full charge. The battery has a thermistor mounted therein which changes resistance as the battery temperature changes. The charger includes a charging circuit and silicon controlled rectifier in series with the battery. A sensing circuit, coupled to the thermistor, senses a thermistor resistance indicative of less than a full charge and changes from a first to a second state. If the thermistor resistance indicates a full charge, the sensing circuit changes from the second to the first state. A switch circuit connected to the sensing circuit and the rectifier gate electrode is responsive to changes from the first to the second state to trigger the rectifier into conduction and allow charging of the battery at the predetermined rate. A latch circuit connected to the sensing circuit and rectifier gate electrode operates in response to the sensing circuit changing from the second to the first state to inhibit further conduction of the silicon controlled rectifier. The latch circuit is deenergized, allowing further conduction of the silicon controlled rectifier, by removal of the battery from the battery charger.

Liquid level control

Abstract: LIQUID LEVEL CONTROL OR INDICATOR CIRCUIT IN WHICH A RESISTANCE BRIDGE IS UNBALANCED BY CHANGE OF LIQUID LEVEL IN A CONTAINER. BRIDGE IS NORMALLY SLIGHTLY UNBALANCED, AND THE DEGREE OF THIS SLIGHT UNBALANCE MAY BE VARIABLE TO CHANGE THE SENSITIVITY. CHANGE IN LIQUID LEVEL SINIFICANTLY UNBALANCES THE BRIDGE TO BIAS A CONTROLLED RECTIFIER, THEREBY TRIGGERING ENERGIZATION OF A PUMP, VALVE, OR SIGNAL OR INDICATOR DEVICE.

Triac motor speed control

Abstract: A motor speed control including a fullwave diode bridge rectifier for rectifying alternating current received from a supply circuit, a triac coupled in a series loop circuit with the bridge rectifier and the supply line for controlling the flow of current through the bridge rectifier during both positive and negative half-cycles of the supply line voltage, and a control circuit for controlling the firing of the triac, the control circuit including a diac coupled in series with a timing capacitor. A speed-setting potentiometer, coupled in series with the timing capacitor, is utilized for selecting the operating speed of the motor.

Switching arrangement for the stabilization and ignition of welding arcs and the like

Abstract: A switching system for the stabilization of alternating-current welding arcs and for the ignition of alternating-current or direct-current welding arcs in which the ignition or stabilization current pulse between electrode and workpiece or between two electrodes is transmitted through a capacitor and at least one semiconductive controlled rectifier (SCR or thyristor) is provided in the discharging circuit of the capacitor. The gate of the controlled rectifier is triggered by a control circuit synchronized with the current source and including a voltage-responsive switching element in circuit with a control capacitor. The voltage-responsive switching element is a DIAC-type trigger diode whose output is connected directly i.e., via only ohmic impedance) with the control electrode or gate of the controlled rectifier.

Solid state power controller for dc permanent magnet and shunt field winding motors supplied from an ac source

Abstract: A solid state switching circuit and power controller for permanent magnet and shunt field winding motors used in portable power tools and the like. The power controller employs a bidirectional thyristor triode and trigger diode for varying the current supplied to the motor armature, and a full-wave rectifier bridge to establish unidirectional current flow through the motor armature on opposite half cycles of the AC power supply. A resistor across the AC terminals of the rectifier bridge enhances control action under light loads.

Loss of phase detector for a polyphase power system

Abstract: The loss of phase detector employs a plurality of rectifiers each of which is connected between a transistor and a corresponding phase of a polyphase AC power system. Each rectifier couples a signal to the transistor when the corresponding phase provides output power. These signals render the transistor nonconductive. When power is lost in any of the phases of the polyphase system or when voltage in the system decreases below a predetermined value, the transistor is rendered conductive so that a capacitor in series with the transistor is charged by a reference voltage which is connected to the transistor. The charge on this capacitor provides a signal that activates an indicating device which warns that power has been lost in one of the phases of the polyphase power system.

Torsional rectifier drilling device

Abstract: The sonic energy output of a sonic generator is coupled to a torsional resonant circuit. The output of the torsional resonant circuit is in turn coupled through an acoustic rectifier device to a drive member such as a cutting tool. The rectifier provides unidirectional high level pulses of resonant sonic energy to a cutting tool causing such cutting tool to be rotationally driven in a pulsating manner.

Control Methods for Improving the Reactive Power Characteristic of HVDC Links

Abstract: Alternative control philosophies suggested for short- distance HVDC links promise improved performance of the inverter as compared to usual constant direct voltage control. Reactive power characteristics are discussed for both inverter and rectifier. The requirements for compensating equipment and the consequences with respect to transmission losses are outlined.

Apparatus for electrically testing a coil including a primary coil and core, a pick-up coil, and limited supply of high voltage d.c. for energizing the primary coil

Abstract: A primary coil and a core are adapted to be magnetically coupled to a test coil. A pick-up coil is also within the magnetic couple and is electrically connected to a detection or indicating means. A limited supply of high voltage D. C. energy is provided by a capacitor bank. At least one silicon-controlled rectifier serves as a switch between the capacitor bank and the primary coil. The silicon-controlled rectifier is triggered through a four-layer diode with a capacitor in parallel with the four-layer diode providing a repetition rate of switching dependent upon its charging time. A defect, such as a shorted turn, in the test coil will be reflected through the magnetic couple and the pick-up coil to the detection means.

Fail-safe solid-state emergency lighting power supply and transfer circuit

Abstract: A self contained power supply unit for standard ''''rapid-start'''' fluorescent lamps employing a full-wave rectifier to charge a battery and a common-collector solid state oscillator circuit employing two PNP transistors which are normally biased to their non-oscillating mode by the charging potential from the full-wave rectifier. The oscillator output is delivered directly to a pair of clamp-on leads respectively anchored to the terminals of a standard ''''rapid-start'''' fluorescent lamp in parallel with the lamp''s normal ballast circuit. The clamp-on leads are connected by only two wires to the oscillator output circuit. The oscillator transistors are normally biased in their nonoscillating mode, and the only power consumed by the circuit is the power required for continuous battery charging, the charging current being drawn through a current-limiting resistor and a diode. In the event of main power line failure, the battery continues to supply the normal DC potential to drive the amplifier, but the biasing potential dervied from the full-wave rectifier is no longer present and the oscillator transistors are therefore no longer biased in their non-oscillating mode. Powered by the emergency battery, the oscillator produces high frequency sinusoidal output current which is delivered through the clamp-on leads directly to the terminals of the fluorescent lamp during main power line failure. When main line power is restored, the full-wave rectifier charging potential is again delivered to bias the oscillator transistors to their non-oscillating mode, automatically returning the emergency power supply unit to its battery charging mode.

Peak current limiting system

Abstract: A very fast acting peak current limiting system for the protection of semiconductor controlled rectifiers or thyristors and associated circuit components against damaging overloads resulting from short circuits. In a rectifier power supply system the input current of which is controlled by semiconductor controlled rectifiers, peak current is sensed on each incoming power line and compared with a preset reference. In event the peak current exceeds the reference, an error signal is generated which actuates a trigger circuit connected to the gate lead of the semiconductor controlled rectifiers to phase back these rectifiers to the nonconductive mode. The rectifiers are then slowly returned to the current threshold. If the overload was caused by a transient condition, normal current will flow. If the overload was due to a persistent condition, the slow return of the semiconductor rectifiers to an overload condition will permit supplementary control systems having a slower time response to control the current into the rectifiers. Such supplementary control system may comprise subsystems to control overloads due to either internal faults within the power supply system or external faults.

Dual battery charger having dual output

Abstract: First and second batteries are connected in series between a point of constant reference potential and the output terminal of a first full-wave bridge rectifier. The output terminal of a second full-wave bridge rectifier comprising silicon-controlled rectifiers (SCR) is connected to a junction between the batteries. The respective legs of the first and second rectifiers are each connected to the same output winding of the stator of an alternator. A first voltage detector responsive to the voltage across the first and second terminals causes the SCR''s to be nonconductive when the voltage across the first and second terminals is less than a first predetermined voltage. A second voltage detector controls the current through the field winding of the alternator in response to the voltage at the junction between the batteries to maintain a second predetermined voltage thereat. The drop in current and therefore voltage at the junction occurring an instant after the SCR''s are rendered nonconductive causes the second voltage detector to increase the current and voltage at the first output to increase by an amount sufficient to reestablish the second predetermined voltage at the junction.

Automotive burglar alarm having battery current flow detector

Abstract: An alarm device is energized when any current is drawn from the battery employed in the electrical system of the automotive vehicle. The onset of battery current is utilized to produce a voltage pulse, which is employed to trigger a silicon controlled rectifier. The rectifier energizes a relay coil which operates relay contacts connected to the alarm device. The voltage pulse preferably is produced by a magnetic pickup coil mechanically coupled to the battery cable of the electrical system. In a second embodiment, the instantaneous battery voltage is compared with the stable voltage across a capacitor charged to the initial battery voltage. Any drop in the instantaneous voltage produces a voltage pulse which triggers the electronic switch. In a third embodiment, two of the leads to the silicon controlled rectifier are connected to the negative battery cable between the negative battery terminal and ground, between which an SCR triggering voltage drop develops when current is drawn from the battery. In each of the embodiments, if the SCR is bypassed initially, it is connected to be latched by avalance operation. The burglar alarm can be encapsulated as a module and can be coupled electrically into the vehicles'' electrical system easily, without any splicing of existing wiring. The magnetic pickup coil of the primary embodiment is subject to sensitivity regulation by way of a clamp which mounts and orients the module with respect to the battery cable.

Power conversion system

Abstract: This invention relates to a power conversion system wherein energy from a high-voltage direct current source is caused to charge a relatively small high-voltage capacitor and the energy stored in said capacitor is transferred periodically through a resonant discharge circuit and rectifier to supply a low-voltage direct current to a load which may, for example, be a large capacitor or a battery whose charge is to be maintained relatively constant

Protection means against auto-ignition for the rectifiers of a static converter

Abstract: In a static converter with thyristor-rectifiers, a protection against auto-ignition includes an arrangement for sensing the polarity over the rectifier, and an And-gate. The sensing arrangement emits a first signal to the And-gate when a voltage after a commutation becomes negative and a second signal when a voltage after a commutation becomes positive. The And-gate is connected to the ignition system of the rectifiers to supply both signals thereto. The connecting means for the first signal includes a delay device which delays the signal by a time corresponding to the longest recovery time for the thyristors, so that, if the second signal is emitted during this time, an ignition signal is allowed to pass the And-gate.

Variable pulse-width pulse-modulator

Abstract: A solid-state pulse-modulator for producing power output pulses from a source of direct current, the width (duration) of which can be varied on a pulse-to-pulse basis within a given range. This modulator does not employ mechanical switches, such as are normally required for variable pulse-width, high-voltage pulsemodulators. More specifically, a group of parallel-connectable resonant-chargeable networks is provided, each including a capacitor and an inductor. A predetermined number of the chargeable networks are charged by gating into conduction one or more silicon-controlled rectifiers located in the charging path. Still another silicon-controlled rectifier is gated into conduction to discharge all of the charged chargeable networks, to produce an output pulse having a pulse-width proportional to the number of chargeable networks that are so charged and discharged.

Circuit breaker including improved current auctioneering circuit

Abstract: A circuit breaker including a current auctioneering circuit for obtaining a unidirectional output current which is substantially equal to the unidirectional output current of only one of a plurality of substantially constant, unidirectional current sources each having a pair of output terminals comprising means for connecting the output terminals of the current sources in series circuit relation between a pair of overall output terminals and rectifier means connected to the output terminals of each current source.

Exciter arrangement for synchronous motors

Abstract: An arrangement for controlling excitation of the field coil on the rotor of a synchronous motor during starting as well as during running at synchronous speed includes a rectifier bridge mounted on the rotor having controllable rectifiers in one bridge half and uncontrollable rectifiers in the other bridge half. The rectifier bridge is supplied with current from an exciter alternator also integrated into the rotor structure. During starting and up to near synchronous speeds the controllable rectifiers are blocked so as to block current flow from the motor field coil through the bridge. Thereafter, these rectifiers become unblocked and feed continuous current to the field coil.

Gate controlled switch transistor drive integrated circuit (thytran)

Abstract: A body of semiconductor material comprises a controlled rectifier switch and a transistor each sharing a common anode. The controlled rectifier provides the base drive which is necessary to keep the transistor in an ''''on'''' condition. Once operating, the transistor functionally does not see the controlled rectifier in the electrical circuit. When it is desired to shut off the transistor, the necessary signal is sent to the gate region of the controlled rectifier and the rectifier is turned off thereby removing the base drive from the base region of the transistor which in turn turns all of the regions of the transistor off substantially simultaneously. This type of device is designated by the term ''''THYTRAN.

Capacitor switching arrangement for regulating power output of heating magnetron

Abstract: In a microwave heating apparatus comprising a magnetron, a plurality of capacitors are provided in the high tension rectifier circuit of the magnetron to vary the power output from the magnetron, and are changed over by the same number of switches as the number of the capacitors.

By-pass connection of static converters

Abstract: A static converter composed of a converter-transformer and a rectifier bridge connected thereto has a bypass member connected in parallel with the bridge. Two series-connected rectifiers in one phase of the bridge constitute a bypass path. A direct voltage source can be connected with said two bypass rectifiers, the source having such a polarity as to furnish a current in the conducting direction of the two rectifiers.

Fluid cooled rectifier holding assembly

Abstract: Disclosed is a cooled pressure assembly for applying clamping pressure to a plurality of semiconductor rectifiers and for electrically connecting them in parallel. The pressure is applied via a pair of heat dissipating electrodes disposed on opposite sides of the rectifiers. Each electrode contains a plurality of heat dissipating fins which make up a plurality of cooling fluid ducts immediately adjacent the rectifiers. Clamping force exciting means are provided to center the clamping forces axially on the rectifiers and to apply them through the electrodes and the fins therein contained to the rectifiers.

High voltage generating apparatus

Abstract: In a high voltage generating apparatus comprising a piezoelectric transformer element for generating a high AC voltage and a voltage step-up rectifier connected to the output electrode for generating a high DC voltage, there is provided a casing divided into two compartments by means of a partition wall for containing the piezoelectric transformer element and the rectifier respectively. Sealing means is provided between the periphery of the partition wall and the inner surface of the casing to electrically isolate the piezoelectric transformer element from the voltage step-up rectifier.

Needle stop apparatus for sewing machine

Abstract: A needle stop apparatus for use in a motor-driven sewing machine, in which the needle of the sewing machine is automatically stopped at a predetermined position by turning off a controlled rectifier connected in series with the motor, said turn off of the controlled rectifier being effected by shortcircuiting a gate trigger signal generator upon detecting that the needle is coming to the predetermined position when the motor is prepared to be stopped, and any manual movement of the needle does not cause the motor to start after a predetermined time interval has elapsed from the motor stop, and further it is possible to operate the sewing machine in a one-stitch mode.

Operating Characteristics of a Three-Terminal DC Transmission Line

Abstract: An evaluation is made of the performance of a three- ended dc transmission line superimposed on an ac network. Tests were conducted both with two rectifiers and one inverter and with one rectifier and two inverter terminals. Performance of these circuit configurations was evaluated under various steady-state and transient conditions.

Induction heating apparatus

Abstract: A circuit for supplying a series of current pulses to an output coil, such as a coil used for induction heating, can be constructed utilizing a timing circuit adapted to be connected to a DC power supply and a resonant circuit including the output coil connected to the timing circuit. The timing circuit used includes a current discharge or release means such as an SCR (silicon-controlled rectifier) and a trigger means such as a trigger diode (bidirectional diode thyristor) for actuating or firing the release means in response to current supplied by the power supply so that the release means will supply current to the resonant circuit. The current supplied to the resonant circuit results in the development of a resonant current in opposition to the supplied current. Such resonant current feeds back to the timing circuit so as to render the release means no longer operative to supply current to the resonant circuit until such time as thereafter the trigger means, as a result of power supplied to it from the power supply, actuates the release means so that it will again supply current to the resonant circuit.

Starting control scheme for rectifier-inverter systems

Abstract: A high-voltage electric power converter comprises a plurality of electric valves interconnected in a bridge configuration. In operation the valves are cyclically fired in a predetermined normal sequence by a series of relatively short gate pulses respectively applied thereto. For successful starting, the controls are arranged (1) to idle until the concurrence of a starting command and a proper instant of time for firing any one of said valves, and then (2) to apply simultaneously a gate pulse to that one valve and a gate pulse to the immediately preceding valve in said normal sequence. The controls are preconditioned so that the initial firing angle is within certain limits that ensure continuous conduction by the preceding valve at least from the starting instant to the time at which the succeeding valve is fired.

Internally resistively ballasted discharge lamp containing bridge rectifier

Abstract: A discharge lamp comprising an arc tube and an incandescible filament connected in series within an outer jacket. An integral four-diode bridge rectifier operates the lamp on rectified alternating current and the filament limits the current through the arc tube. The lamp operates reliably with a greater proportion of the line voltage applied across the arc tube than in conventional resistively ballasted lamps, resulting in higher efficiency. One or more diodes may be paralleled by a small capacitor to provide a voltage doubling effect to start the lamp.